|The really cool feature about the rear brake is this integral steel parking brake drum combined with a full floating lightweight alloy hat. You can ebrake to your heart’s content and not worry about the brake shoes damaging the soft alloy.|
Simply bolting a universal racing brake set up to a street car’s single master cylinder hydraulic system usually results in an unbalanced brake bias. This is one of the reasons why many aftermarket big brake kits have a longer than stock stopping distance and suffer from premature lock up, usually of the front wheels.
|Here is the drum parking brake if you were wondering what we were talking about. The parking brake on the BMW is a separate unit inside the rear rotor.|
Performance Friction designed their brake system around the 135i and its hydraulic system. The car’s weight distribution and suspension geometry were examined as well as the stock hydraulic proportioning. The geometric mechanical advantage of the calipers due to caliper mounting position and rotor size was considered as well to model what the overall brake bias balance would be in static and dynamic simulation. The piston sizing of the Performance Friction calipers was configured using this data to give the proper brake bias. This level of engineering ensures that the brake system will not suffer from poor bias which can negatively affect stopping ability and stability. It also makes sure that the vehicle’s electronic systems will continue to function well.
|Our new rear brakes look mighty slick. We opted for dimpled rotors. They don’t have thru holes that promote cracking but still evacuate the firebrand area of the pad’s rotor interface.|
The Performance Friction caliper’s pistons are unique as they are buried deep within the caliper’s body, isolated from heat and protected from seal wearing brake dust and debris. A large diameter cap covers the piston and provides a large surface area for the pad to bear upon to better distribute the braking force. A PFC-specific patented heat resisting shield separates the piston cap from the actual piston and greatly reduces heat transfer to the brake fluid. On the street versions of the caliper, a full bellows type dust boot prevent contaminants from coming near the seals. This is important for a long maintenance free life on a street car. For racing use the bellows are omitted which is standard practice for all racing calipers as they would be destroyed by racing levels of heat. The seal’s geometry is designed to optimize piston retraction to ensure cool drag free operation with a consistent pedal. The calipers forged aluminum body has stainless steel abutments for the brake pads to ride in to ensure smooth application, low wear and positive pad retraction without bind. These abutments are aligned with the direction of brake force induced torque to reduce overall stress and flex within the caliper and mounting system.
|The PFC rear rotor dwarfs the stock part. It’s still lighter.|
|The PFC caliper has a lot more pad area. With proper piston sizing the proportioning works out fine.|